We are trying to setup announcements using SharePoint 2010 alerts to distribution group email@example.com. This distribution group cant receive emails from unauthenticated users.
We configured under SharePoint Central Admin Console the Outbound SMTP Server, From Address:, Replay-to address:, Character set properly. FROM: is setup to firstname.lastname@example.org
Also created AD user SharePoint which is a Domain User, has its own mailbox email@example.com.
We used MS TechNet to configure SMTP server on IIS @ SharePoint server https://technet.microsoft.com/en-us/library/cc288949(v=office.14).aspx
, instead of using anonymous user we used the same AD username sharepoint with its own password, thinking it will get authenticated this way. We also restarted IIS and sharepoint services.
Under exchange we added ourselves to Full Manage mailbox so we can see returning emails if any.
We then created a new announcement, alert triggered and message came back to firstname.lastname@example.org with error 550 5.7.1
#550 5.7.1 RESOLVER.RST.AuthRequired;
authentication required ##
For testing we unselected the authenticated user requirement, created new alert and emails alerting that new announcement was created were received to email@example.com.
As per security policy we need to have a required authenticated user sending emails to this distribution group.
What is the simple fix is any to go around the problem.